Clutch and transmission



Jan.4, 1944. J. DOLAN 2,338,693

CLUTCH AND TRANSMISS ION Filed Jan. 1o, 1940 5 sheets-sheet 1 v f 63 5 4, 2i?. ,50 5 i J4 .67 y 22:; .35 v lf 53 5% 3i; A A 549'/ Y //5 2.? A 55 2` 4Z ATTORNEYS CLUTCH ND TRANSMISSION Filed Jan. 10. 1940 5 Sheets-Sheet 2 IN ENTOR nv/ .7'. mmv

f AATTORNEYS BY www Jan. .4, 1944.

D. J. DoLAN CLUTCH AND TRANSMISSION 5 Sheets-Sheet 5 y 50mm @W3/7^ Filed Jan. 10, .1940

IN dDfw/za .73 uw ATTORN EYS 5 Sheets-Sheet 4 #ccf/.ffm rok Psw/ D. J. DOLANy CLUTCH AND TRANSMISSION Filed Jan. l0, 1940 INM/ 5 NAN/Fam l ENTOR oL/y/v ATTORN EYS Jan'. 4, 1944.

Jan. 4, 1944. l E,` 1 DOLAN A2,338,693

f I CLUTCH AND TRANSMISSION 4 Filed Jan. 10, 1940 l 5 Sheets-Sheet 5 INVENTOR DH v/D J: .Pac/9N ATTORN EYS Patented Jan. 4, 1944 CLUTCH TRANSMISSION David J. Dolan, Cleveland Heights, Ohio; Corinne C. Dolan administratrix of said David J.

deceased Dolan,

Application January 10, 1940, Serial No. 313,262

27 Claims.

This invention relates to a clutch and transmission and, more particularly, to a fullly automatie clutch which is actuated directly by differ'- ential uid pressures and to a geared transmission which `is automatically selective in response to load demands.

`In the prior artr automatic clutches for automobiles and the like have generally employed either powered actuating mechanisms to engage or disengage a conventional friction clutch. or

have employed a liquid as the connection between the driving and driven members of the clutch. In automatic geared transmission, the several stages of speed reduction are usually accomplished by employing powered actuating mechanisms which engage or disengage the gear-- ing in the several steps of speed reduction.

It is an object of this invention to provide a fully automatic clutch which eliminates the need for powered actuating mechanism for engaging or disengaging the clutch/and which does not require a liquid connection between the driving and driven members. This yobject is accomplished by employing the manifold vacuum of an internal combustion engine to evacuate the space included between the driving and driven members of the clutch whereby the ambient atmospheric pressure forces the driving and driven members into a secure frictional engagement. Another object of this invention is t'o provide a friction clutch which is smooth acting but which does not Fig. 1 is a section taken along the axis of a. clutch made according to this invention;

Fig. 2 is a detailed fragmentary section taken along the line 2-2 of Fig. 1;

Fig. 3 is a detailed fragmentary plan view taken from the line 3-3 of Fig. 1 showing a lead lug;

Fig.,4 is a section taken along the line 4 -4 of Fig. 1

Fig. 5 is a section taken along line 5-5 of Fig. 1;

Fig. 6'is a section taken Ialong' line 6-6 of4 Fig. l;

Fig. 7 is a detailed fragmentary -plan view taken from the line 'I-l of Fig. 4;

Fig 8 is a detailed fragmentary section ltaken along the line 8 8 of Fig. 7; l

Fig. 9 is a diagrammatic View illustrating the clutch control system;

Fig. 10 is a, detailed diagrammatic sectional view illustrating the control valves;

Fig. 11 is a section taken alpng the axis of a transmission made according to this invention;

Fig. 12 is a detailed fragmentary elevation taken from the line I2-I2 of Fig. 11; and

Fig. 13 is a detailed fragmentary plan view taken from the line IS-Ilof Fig. 12.

In the drawings, in which like reference characters refer to like parts, the construction of a require the use of friction material between the driving and driven members.

A further object of this invention is to provide a geared transmission which is fully automatic and which passes from one stage of speed reduction to an adjacent stage of speed reduction smoothly and without passing through a neutral and without the use of powered actuating mechanisms for changing th'e drive from one ratio'to another ratio. Y

A still further object of this invention is to provide a control system for a clutch and transmission responsive to the actuation of the 'throttle and brake of an automobile which will regulate the operation of the clutch and transmission.

made according to this invention is that it is sirnple and positive in action and may be manufactured at substantiallyno more cost than' con.. ventional manually operated clutches and transmissions.KV Other and further objects and advan- An advantage of a clutch and transmission tages will appear from the following specification, claims, and drawings in which:

clutch made according to this invention is illustrated in Figs. 1 to 8. A driving shaft I, which is normally the crank shaft in an internal combustion automobile motor, is provided with a socket toreceive the pilot 2 of an aligned driven shaft 3, which, in the embodiment shown in Figs. l to 10, maybe'connected to a conventional automobile transmision. A flywheel 4, preferably of stamped sheet steel construction in order to reduce weight, is keyed to the end-of the driving shaft I and carries a starter ring gear 5 suitably secured to the ny-wheel rim.

The fly-wheel I and-the improved clutch Ill are enclosed within a housing ,t which is usually fixed to the automobile motor block, the 'clutch Il being carried by the driven shaft I. A"clutch plate hub II is keyed to the end of the driven plate lz;

shaft 3, thereby securing the clutch which isv integral with the hub II, to \the shaft,l ,3.

The clutch plate* I2, as shown in Figs. 1 and', is preferably a steel-disc -on both sides of integral linner sealing rings I3 and outer friction rings Il are carried. 'I'he sealing ringer/I3 and and friction rings I4 are preferably of/ graphite bronze or a similar bearing metan/welded to l the steel clutch plate I2.. In ordeif: to prevent the clutch plate I2 from dishing or warping under load, a. plurality of openings I in the central portion` of the plate I2 and radial slots I6 extending across the friction rings I4 are provided. The openings I5 and slots AI6 alsov permit the passage of air through the plate and prevent air from being trapped on substantially any portion of the surfaces of the plate I2. As shown in Fig. 5, the-several openings I5 and slots yI6 are so arranged that portions of their orbits coincide so that air picked up, for example, in the slots I6 may pass to the openings I5.

The clutch plate hub I I carries a bushing I1 on which is rotatably mounted the flanged hub 2I of the face plate 26. The clutch plate hub I I also carries a bushing I8 on which is rotatably mounted the flanged hub 3I of the face plate 30. The annular spaces between the hubs 2| and 3| and the shaft 3 are sealed by the packing washers I9 which prevent the leakage of air into the space.

to the adjacent bearing ring I3 anddriction ring' I4 of the clutch plate I2. While the clutch is disengaged, enough clearance is provided between the ring I4 and surface 24 to provide a good running fit, i. e., the clearance is preferably at least.

four-thousandths of an inch. A spiral groove 2'5 is cut in the friction surface 24 in order to prevent air from being trapped thereon. The outer surface of the face plate 20 is provided with a plurality of fins 26 which stiifen the plate and aid in the dissipation of heat generated during actuation ofthe clutch.

. The face plate 30 is substantially similar to 40 lface plate 20, being provided on its inner surface with a shallow channel 32,'an annular bearing surface 33, and a friction surface 34 which has a spiral groove 35 in :the facethereof. The` clearance between the friction surface 34.and the adjacent frictionv ring I4 while the clutch is disengaged is also suillcient to provide a good running fit. The outer surface of the face plate 3Il'is provided, with a plurality of stiffening and 'heat dissipating ns 36. A An annular sealing groove 21 is cut inthe friction surface 24 of the plate 20 adjacent the periphery thereof, and a similar groove 31 is cut in the plate 30. A packing ring 28, preferably of cork composition or the like, is fittedv in the grooves 21 and 31, thereby sealing off the space included between the inner surfaces of the face plates 26 and 30, I

Relative movement of the plate 2li-with respectl to the plate 36 is restrained by the several resilient load dogs 46 located on the rims of the plates 26 and 36. Preferably, as shown inFlg. 3,

- each dog 40 comprises a block of rubber 4I, to the ends of which are bonded or otherwise secured the brackets 42 and 43. The bracket 42 is riveted or otherwise secured to a lug 29 which'is integral 26 and 30 with respect to each other when the clutch is disengaged, but their primary function is to absorb shock loads. while the clutch is engaged oris .being engaged since the plate 20 tends to lead the plate 30 in the direction of rota-v tion when the clutch is under load. i

A positive limit to the lead in the direction of rotation of the plateA 20 with respect to the plate.

5 30 is provided by the several pairs of wedging lugs 44 and 46, which are also located about the rims of plates 26 and 30. In each pair of wedging 1ugs, the 111g u is integral with the plate zo A and is.provided with a wedge face 45; the lug 46 comprises an angle secured tc the plate 30, one

arm of the angle overlying the rims of the plates and being provided with a Wedge ear 41 corresponding to the wedge face 45. In order to absorb the shock of the engagement of the lugs 44 and 46, a rubber wedge face 48 may be bonded to the wedge ear' 41. The amount of clearance between the wedge lugs 44 and 46 limits the amount of rotary movement in the direction of rotation of the plate relative' to the plate 30. As shown in 20 Fig. 7, which illustrates the lugs 44 and 46 under tion of rotation, the lug 46. When the load on plate 26 to lead the plate 36 overcomes the resistance of the dogs 40, the engagement of the lugs 44 and 46 not only prevents further relative rotary -movement of the plate 26, but the wedgling action ofthe lugs tends to force the plates ment of the clutch plate I2 by the face plates 26 and 30 when there is a large torque load on the clutch, y

The torque of the driving shaft I is transmittedthrough the ily-wheel' 4 to the face plate 20 through the several resilient key blocks 56 which are fitted in sockets 5I in the fly-wheel 4 and are supported laterally by hns 52 which are integral with the ily-wheel. The key blocks 56 are preferably of rubber and each key block is provided with a radial groove which receives a n 26 of the face plate 2li. The key blocks 50 are prevented from being dislodged radially by the short arcuate fins 53 and 54 on the face plate 20; In order to ventilate the clutch housing 6 .and to dissipate'heat generated by actuation of the clutchinlets 55 are provided in the ily-wheel 4 to admit air adjacent the hub of the face plate 20, and inlets 56 are provided in the housing 6 to vadmit air adjacentthe hub of the face plate` 3U. As theclutchis driven, the fins 26 and 36 blow the' admitted air through the outlets 51 in the outer wall of the-.clutch housing 6.

The clutch- I0, which is normally disengaged, f

-is engaged by evacuating the air from the sealed space included between the clutch plates 2liv and 36 so that the atmosphere^ on the outer surfaces of the face plates 20 and 36 force them into engagementrwith the clutch plate I2. In order to evacuate the clutch IIJ; the face plate 36 is pro-'- o vided with a plurality of ports 66 which extend through the integral port ring 6I ..of the plate 30. The port ring 6I. which is provided with lsuitable packing, is rotatably received in the annular commutator groove 62 of the fixed'collector ring 05 63. vThe com mutator groove is provided with a collector groove 64 into which the ports 60 open. .the collector groove 64 being connected by the" passage 66 to the collector ring nipple 66, which may be connected by suitable tubing to an-in- 70 ternal combustion, engine manifold, the normal source of vacuum supply.

czut'ch operation The operation of the clutch disclosed 1n Figs. 1

7s 8 is as follows: Torque from the driving shaft no load, the lug 44 is located behind, in the direc- 26 and 3D together, thereby assuring the engage-` I is transmitted by the ily-wheel 4 ailixed thereto through the resilient rubber key blocks 5I) to the face plate 20, which, when the clutch I0 is disengaged, is freely rotatable on the bushing I'I. The face plate 30 is also freely rotatable on its bushing I 8, and, because of resilient connection offered by the load dogs'40, tendslto rotate as a unit with the face plate 20. s

` With the vacuum supply line connected tothe nipple 66 open to the atmosphere, air is supplied to all portions 'of the space included between the plates 20 and 30 through the `passage 65, collector groove 64, and ports 60, whence it is disthe clutchl III, therefore, may begin to slip under a heavy load.

It the clutch I0 does begin to slip, the drag of the friction ring' I4 on the friction surface 34 ',will cause the face plate 30 to lag behind the face plate 20 until the wedge lug 44 engages the f wedge lug 46, therebycausing the faceplates to tributed by 'the openings I5 and slits I6 in the .l

clutchA plate- I2 and by the spiral grooves 25 and" 35, respectively of the face plates 20 and 30. Al-

though the clearance betweenthe face plates 20 conditions.

tial on the face plates and 30 is insufncient and and the clutch plate I2 is preferably 4and the packing ring 28, when air is evacuated from the interior of the clutch by connecting the 'nipple 66 to a source of vacuum, the atmospheric pressure on the outer surfaces of the face plates forces them to move axially toward, each other, thereby engaging the friction surfaces 24 and 34 with the friction rings I4, thereby transmitting the torque of the driving shaft I through the clutch plate I2 and hub II to the driven shaft 3. Of course, when the line to the nipple 66 is reopened to atmosphere pressure, the differential pressure on the face plates drops to zero almost immediately and the resilient load dogs lreturn the face plates-to their normal disengaged positions. Because the face plates 26 and 30 are light and the distances which they have to vmove from their engaged to disengaged positions are almost undiscernible, the clutch is acutely responsive.

It is apparent from the foregoing that the amount of torque which can be transmitted by the clutch disclosed is directly proportional to the differential between the atmospheric pressure on the outer surface of the face plates and vacuum within the interior of the clutch. If, in

the clutch disclosed, the diameter of the clutchis 11.5 inches, each face platevthereby having an 4 area of approximately 100 square inches, the total pressure on the friction rings I4 is one thousand pounds, when the automobile engine is opcrating under a`normal load and speed with a manifold pressure differential of iive'pounds per square inch; Allowing for a, static coefficient of friction of .95 between the friction rings I4 and friction surfaces 24 and `34 and an effective radius of 5.5 inches for the friction rings I4, the v drop to .5 pound per square inch, in which case be forced together mechanically into engagement with the clutch plate I2; Since the wedge lugs 44 and 46 may afford a mechanical advantage of ten, under the aforesaid heavy load conditions in which the total pressure of the plates 20 and 30 may be only one hundred pounds, the action of the wedge lugs will increase the pressure of the plates to one thousand pounds, which, as pointed out above, will be ample for any load Thereforeif the pressure differento drive ,the clutch plate I2, the'wedge lugs 44 and 46 will insure a positive drive.

It is also apparent from the foregoing that the rate of engagement f the clutch is directly proportional to the rate at which the difierential pressure on the face plates is created, and since the rate of increase in the differential presi sure may be controlled readily by metering the vauum supplied to the nipple 66, the responsiveness of the clutch may be regulated. The clutch operates smoothly even though theengaging surfaces of the clutchfare metal, which, in this eral factors, the relative importance of which' has not been determined, namely, the resilience of the connecting members, i. e. the key blocks 50. load dogs 40,-and the wedge faces 48, the controlled responsiveness of the clutch, the cooling of the face plates'20 and 3h by the considerable volume of air drawn by the fins 26 and 36 through the inlets and 56 and expelled through the outlets 51, and the lubricating effect of` the air within the lclutch which is entrained by the fricv tion surfaces 2 4 and 34. Because the clearances between the friction surfaces 24 and 34 and the friction rings I4` areslight, it is believed that the air distributed over thefriction surfaces by the.

spiral grooves 25 and 35 and the slits I5 behaves as any low viscosity fluid and actually -lubricates the friction surfaces. As air is gradually evacuated from'within the clutch, the lubricating ac tion of the entrained air gradually decreases, vthereby accounting for lthe smooth engagement' Y of the clutch.

Control systen The system of tube lines for controlling the clutch III when used in an automobile is shown diagrammatically in Figs. 9 and 10. The direct the *totall pressure on the friction rings will be only 100 pounds per square-inch and ,the torque which hev clutch'can transmit without slippage will be not more than 43.5 foot-pounds, so that manifold line I0 leads from the intake manifold of the engine to a manually adjustable metering valve Il from which one branch line I2 leads to the accelerator valve 80 and another clutch supply line I5 which connects the brake valve 9|) to the nipple 66. An Vauxiliary vacuum storage tank I6 is connected to the manifold by the line 'Il and to the accelerator valve 60 by the line 18. Suitable auxiliary tank check valves 19 Vbelowthe piston 9| is open to the are placed in the lines 16 and 11 above the manifold.

'I'he accelerator valve 86 is preferably a piston I sage 83 extending almost to the end of the piston 8| and being made conical so as to serve as a metering valve passage. Inone side of the valve 88 are located a port 84 which is connected to the manifold branch line 12 and a port 85 which is connected to the auxiliary tank line 18, the port 85 being located below the port 84 a distance somewhat less than the travel of the piston 8| and capable of being connected to the port 84 by the valve passage 82, On the other side of the valve 86, in line with the passage 83, and located just below the bottom of the piston-8| when the piston' is in its uppermost or normal position, is the port 86 which is connected to branch 14 of the clutch supply line 15. In the bottomv of the valve 86 is located to the vent port 81 which is connected to the brake valve 80 by the vent line 88 and its branch 89.

The brake valve 96 is also a piston valve in which the Apiston 9| y is provided with a valve passage 92. In one side of the valve 96 la vent port 93 is located af distance equal to about onefourthfof the piston travel below the top of the piston 9| when it is in its uppermost or normal position, and another vent port 94 is located just below the bottom of the piston 9| ywhen it is in its normal position. The port 93 is connected to the branch vent line 89 and the port 94 is connected to the vent line 88. On another side of the valve and Yalined with the passage 82 are ports 95 and 96. When the piston 9| is in its normal position, the port 95 is' located belowthe top of the passage 92 a distance equal to about one-fourth of the piston travel and the port 96 is located just below the bottom of the passage 92. The port 95 is connected to the manifold branch'line 13 and the port 96 is connected to the clutch supply line 15. .The portion of the valve 9|)l above the piston 9| is open to the atmosphere through the vent 91 and the portion atmosphere through the vent 98. i

Control system operation yaccelerator pedal, which operates the valve 80 and the brake pedal, which operates the valve v9|). Under such conditions both valve pistons ,8| and 9|are in the position vshown in Fig. 10

andthe clutch I6' is disengaged, since the clutch supply linel 15 is open to atmospheric pressure 'through the branch 14, port 86, port 81, vent line 88, port 94, and vent 98.r

- With vthe manually adjusted'metering valve 1| at the desired setting, the operator steps onpthe accelerator pedal thereby moving the valve piston 8| downwardly, the brakel valve piston 9|, of i Y pressed slightly in response to a light touch on course, remaining in 'its normal positionso that only the vent port 94 is open., It should pointed out here that the function of the metering'valve 1I and the metering portion of the valve passage 83 is to regulate the rate at which the differential pressure in the clutch I6 is created and does not ailect the total differential pressure which may be created in the clutch. The function of the metering valve 1| is to set a basic rate of change in 'differential pressure, which basic rate may be further varied by the metering passage 83,v depending upon the position of the piston 8| in the valve 80. Thus,.as the piston 8| moves downwardly in response to the operators actuation of the accelerator pedal, the

bottom of the. piston 8| iirst begins to close off the* port 88 to the vent port 81, and, though the clutch is still disengaged, during this initial movement, slack is taken up in the throttle linkage operated by the accelerator pedal and the throttle may be opened slightly to start the engine over idling speed, Asfthe piston continues to move downwardly, the port 86 is opened to the passage 83 and the clutch I6 is engaged by the vacuum supplied from the intake manifold through line 10, line 12, port 84, passage 82, passage 83, port 86, line 14 and line 15, which is the ordinary manner in which the clutch I0 is engaged during normal operating conditions. From the foregoing, it should also be apparent that if the operator actuates the acceleratorn slowly in order to start the automobile slowly, the meter passage 83 will open the port 86 slowly, thereby securing a gradual engagement of ahe clutch. However, if the operator wishes to start the autokmobile quickly, he will depress the accelerator the gradual decrease will permit the wedge lugs 44 and 46 of the clutch to` engagegradually so that if the storage tank 16 is taxed beyond its capacity, the clutch will remain engaged without slip discernible to the operator.

The vacuum storage tank 16 is brought into action when the valve piston 8| is almost fully depressed, thereby opening the port 85. When the port 85 is opened, the vacuum in the tank 16 will normally be higher than the vacuum in the manifold and both check valves 19 will be closed. Vacuum for engaging the clutch I0, therefore, will be supplied from the tank 16 to the clutch I0 `through line 18, port 85, passage 82, passage 83,

port 86, line 14, and line 15. When they piston 8| is returned to a, position which closes the port 85, the check valves 19 will open, thereby supplying vacuum to the clutch directly from the manifold inthe normal manner through rthe line 10 l and replenishing the vacuum reservoir through the line 11.

If the car is moving and the operator's foot is oi both the accelerator and brake pedals, the clutch I0 will be disengaged in the same manner as during idling. `Thus,` the automobile will free-wheel." If the brake valve piston 9| is dethe brake pedal, the vent port 94 will be closed and the lport 96 will be opened, thereby engaging the clutch I6 by supplying vacuum through the line 16, line 13, port 95, passage .92, port 96, and

clutch supply line 15. Thus, the automobile may be taken out of free-wheeling by'depressing the brake pedal slightly, which will not, of course, cause appreciable wear on the brake;

Because the upper end of the valve passage 92 normally extends above the port 95 a distance equal to about one-fourth of the valve piston travel, the clutch will be engaged during the rst fourth ofthe brake piston valve travel. As the piston 9| moves farther down,`however, the top of the passage 92 closes oil' the port 95, thereby cutting oif-the-supply of vacuum tothe clutch through the port 96 and line 15 and the top of the piston 9| opens .the vent port 93, thereby disengaging the clutch by admitting atmospheric pressure through the vent 91, vent port 93, branch line 89, vent line 88, port 81, port 86, and line` 14 to the clutch supply line 15. Thus, the clutch is disengaged when the brake is applied heavily and the motor `cannot be stalled by the brake, unless, of course, the accelerator is actuated simultaneously. Since the operator normally operates the brake orv accelerator with the same foot, the engine will stall by deliberate operation of the operator, but under no other circumstances.

Transmission clutch train The construction of a transmission according the fins 336 adjacent face plate 330. Suitable openings 339 are provided between the plates 220 and 330 so that air may pass to the fins 336.

The clutch plate 3| 2 of the clutch 3|0 is keyed to the shaft 303 by means of a suitable hub and to this invention is illustrated in Figs. 11 to 13 in which a driving lshaft I, normally the crank-4 shaft of an automobile engine, carries a fly-Wheel 4 which has the usual starter ring gear 5 affixed to its rim. The end of the driving shaft'l is provided with a socket to receive the pilot of an aligned stub driven shaft 303. Concentric with the shaft 303 is a. tubular stub driven shaft 203 which is spaced from the shaft 303 by suitable bushings 201. Spaced from the shaft 203 byv bushing |01 is another concentric tubular stub driven shaft |03, the shafts |03, 203, and 303 being movable a slight distance axially with respect to 'each other. A

The train of clutches H0, 2|0, and 3|0 are carried by the stub shafts |03, 203, and 303, respectively, and are enclosed with therfly-Wheel 4 within the clutch housing 6. Mounted on the end of the clutch housing 6 but suitably spaced there from to provide a cooling air space 8 is the gear box 9 which houses the transmission gearing 400. y

Integral with the shaft |03 is the clutch plate ||2 of the clutch I|0. The clutch plate ||2 carries a false hub l| through which extend the auxiliary Ventilating openings |58. Clutch plate ||2 is also provided with sealing rings, friction rings II4, and openings ||5. The false hub carries the bushings '||1 and |I8 on which are rotatably mounted the face plates and`|30. The'face plates |20 and |30 are each provided with sealing surfaces, friction surfaces |24 and |34, and spiral grooves |25 and |35respectively, and the space included between the face plates |20 Yand |30 is sealed by the packing ring |28. The face plate is provided with fins |36, but the face plate |20, however, is integral with the fins 236 of the adjacent face plate 230. Suitable openings 238 are provided between the plates |20 and 230 so that air may pass through the openings |58 and 238 to the fins 236.

'Ihe clutch plate 2|2 of the clutch 2|0 is integral with the shaft 203 and is provided with sealing rings,4 friction rings 2|4, and openings 2|5. On either side of the plate 2|4 are located the bushings`2|1 and 2I8 on the stub shaft 203. 'I'he face plates 220 and 230 are rotatably carried on the bushings 2|1 and 2|8, respectively, and are provided with sealing surfaces, friction surfaces 224 and 234, land spiral grooves 225 and carries a false hub 3|| provided with suitable openings 359 through which air may pass to Athe openings 239. Clutch plate 3|2 is also provided -with sealing rings, friction rings 3|4, and openings 3|5. 3|1 and 3|8 on which are rotatably mounted the face plates 320 and 330. The face plates 320 and 330 are each provided with sealing surfaces, friction surfaces 324 and 334, and spiral grooves 325 and 335, respectively, and the space included between the face plates 320 and 330 is sealed with the packing ring 328. The .face plate 320 is pro-l vided with fins 326 for cooling and stiiening the plate.

From the foregoing, it is apparent that the construction of each of the clutches' ||0, 210, and 3 I0 is substantially identical to the construction of the clutch |0 described heretofore, andv the location and function ofthe similar elements in the several clutches are substantially the same 'as in the clutch I0. Relative movement between theface plates |20 and |30, 220 and' 230, and 320 and 330 is restrained by the resilient load dogs |40, 240, and 340, respectively. A positive limit to the lead in the direction of rotation of the plate |20 with-respect to the plate |30 is pro-` vided by the several pairs of wedging lugs |44 (not shown) and |46 which are similar in construction, location, and function tothe wedging lugs 44 and 46. No positive limit is required on the clutch 2|0, but a limit is provided on the clutch 3|0 by the several wedge lugs 344 and centrigugal locking arms 346. As shown in detail in Figs. 12 and 13, wedge lug 344 `is located on the rim of plate 330 and is provided with a wedge face 345. Locking arm 346v 1s pivoted adjacent the rim of plate 320, one end of the arm extending across the plates 320 and 330 and being provided with a wedge face 341 corresponding with the wedge face 345. On the other end of .the pivoted arm 346 is located a weight 348; a spring 349'under tension normally holds the weighted end of the arm 346 in the retracted position shown in Fig.' 12. When the centrifugal force on the weight 348 exceeds the tension of the spring 349, the weighted end of the arm 346 moves outwardly, causing the wedge face 341 to engage the wedge face 345, thus forcing the plates 320 and 330 together and thereby insuring the engagement of the clutch 3|0 at a predetermined rotary speed.

As in the clutch I0, the torque of the driving shaft is transmitted through the fly-Wheel E to the face plate 320 through the several resilu ient key blocks 50, preferably of rubber, which are carried in sockets `5| and are provided with. radial grooves which engage ribs 326 of the plate 320. Short arcuate fins 53 and 54 prevent the key blocks 50 from being dislodged radially.,

Since the face plates 330 and 220 and'230 and |20 are integral through the ns 336 and 236,

The false hub 3|| carries bushings In order to ventilate the clutch housing 6 and to dissipate heat generated by the several clutches, inlets 55 are provided in the fly-wheel 4 to admit air adjacent the ns 326, and auxiliary inlets 53 are provided to 'admit air to the 'fins 336 'through the openings 353 and 333. In-

,outer wall of the clutch housing 6.

The train of clutches ||0, 2|0, and 3I0 are engaged by' evacuating air from the sealed space within the clutches, the sealed space of the clutch 3|0 being connected tov clutch 2|0 by the ports 360 and the clutch 2|0 to the clutch lin by the ports 260. Thus, the entire train of clutches may 'I'he spur shaft 4|0 is journaled in the gear box 9 and carries the spur pinion cone 440. 'I'he spur pinion cone 440, keyed to the spur shaft 4|0, is

comprised of the integral first pinion 44|, which y meshes with the rst gear 40|, second pinion 44,2, which meshes with the second gear 402, and the spur pinion 444, which meshes 'with'- the spur gear 404. Spaced from the spur pinion cone 440 and keyed to the spur shaft 4|0 is the reverse pinion 445 which meshes withthe reverse idler pinion 455, which is supported on the stub shaft 453. When the reverse coupler-gear 405 is retracted so that the shaft 303 is uncoupled from the shaft 404, the coupler gear 4051s fully meshed with the reverse idler pinion 455.

' Transmission operation Assuming that the transmission ,disclosed in Figs. 1l to 13 is employed in an .automobile embe evacuated through the ports |60 ofthe port ring |6| which is integral with the clutch plate |30, although the b'oreor number of ports |60, 260, and 360 preferably are progressively smaller. The portv ring |6| is received in the xed collector ring 63, and the-nipple A66 is usually connected by tubing tothe manifold of an internal combustion engine in the same manner described The transmission gearing 400 in the gear box 0 consists of a first speed forward, which employes the maximum speed reduction, a second speed forward, which lemploys an intermediate speed reduction, and a third 'speed forward,.or direct drive, and two speeds in reverse which drive `from the first and second forward speeds through the reverse idler pinion.

The transmission gearing 400 comprises a rst gear 40| keyed on the end of the stub shaft |03; beyond the rst gear 40| is the second gear 402 keyed to the end of the stub shaft 202. and beyond the gear 402 is the spur gear 404 keyed to the stub shaft 303. The end of the stub shaft 303 is provided with a pilot which is received in a socketl of the aligned driven shaft 403, which is usually the drive shaft from the transmission to the dierentialof the automobile. The re-v verse coupler-gear 405 is splined on the shafts 303 and 403 and in its normally disengaged position, as shown in Fig. 11, acts as a sliding coupler for the shafts 303 and 403. The reverse gear 405 is slid in and out of mesh by a yoke 401 which runsv in a ring groove 406 on the reverse couplergear 405. The means for operating the yoke 401 (not shown) may be either a directly manually Y operated linkageor a manually controlled power operated linkage.

Therst gear 40| comprises an integral key ring 4|I, an annular over-running clutch 42| mounted on the ring 4||, and a gear ring 43| supported on the clutch 42|. The gears 402 and 403 are likewise comprised of concentric key rings s 4|2, over-running clutch 422, and gear ring 432 and ring 4|4, clutch 424, and ring 434. The hand of the clutches 42| and 422 is so directed that the clutches engage when the gear rings tend to lag behind the key rings and disengage Lor over-run when the gear rings tend to lead the key rings. The fhand of clutch 424 is oppositely directed so that the clutch engages when the gear ring 434 leads the key ring 4|4 and over-runs when the gear ring tends to lag behind the key ring.

ploying a vacuum'gcontrol system similar to that disclosed in Figs. 9 and 10 and that the automo-v bile is at a standstill, the operation of the transmission is as follows: With the engine idling, the vacuum line to the nipple 66 is open kto atmospheric pressure and the train of clutches is` disengaged. When the operator steps on the accelerator, however, the manifold line to the nipple` 66 is closed and air commences to be evacuated from the interior of the clutch train, creating a pressure differential which causes the several mating face plates to move togetherl and engage the clutch plates enclosed between them. Because the face plate 3|2 is fixed to the stub shaft 303 and the adjacent faceplates of the clutches 3|0, 2|0, and l0 are integral, the clutches 2|0 and ||0 move axially toward the clutch3i0, and, even though the clearance between several face plates and clutch plates is slight, suflicient clearance between the several clutches and gears and axial movement of the tubular stub shafts should be allowed to accommodate the axial movement of the clutches during engagement. l O

At the instant the mating face plates of the several clutches are brought -into engagement with their respective clutch plates, all of the face plates move substantially as a unit with the flywheel 4, and since the several clutch plates are held stationary by the starting load on the driven shaft 4o3,a11 of the clutches Ho, zio, and alo slip. Because the clutch ||0 drives through the gearing having the maximum speed reduction, the starting torque which the clutch ||0 must overcome is the least of the starting torques on the three clutches, -and thus, as the pressure differential'on the `clutches increases, the clutch i0 is the rst to become engaged and the auto mobile is driven in what is conventionally known as rst" from the driving shaft I, fly-wheel 4, key blocks 50, face plate 320, load dog 340, face plate 330, face plate 220, load dog 2 40, face plate 230, clutch |I0, stub shaft |03, first gear 40|. first pinion 44|, spur pinion 444, spur gear 404, stub shaft 303, coupler-'gear 405, and driven shaft 403. 'Although the primary reason for the clutch ||0 engaging and driving the car under normal starting conditions is that the starting torque which the clutch ||0 must overcome is the least, the engagementof the clutch ||0 is aided by the fact that the bore or number of the ports |60 is greater than that of the Ports 2,338,693 |20 and |30 and clutch plate I I2 in the clutch all rotate at engine speed. In the clutch 3I0, however, the face plates 320 and 3,30 rotate at engine speed but the clutch plate 3I2, being integral with the shaft 303, rotates at the speed of the driven shaft 403 so that Ithe ratio of slip in the clutch 3I0 during first is equal to the ratio of the rst gear. In the clutch 2I0, the face plates 220 and 230 rotate at engine speed, but the clutch plate 2|2, being driven from the second pinion 442 through the second gear 402 and stub shaft 203, rotates at a speed intermediate of the speed of the clutch plate II2 and the speed of the clutch plate 3|2, and the slip of the clutch 2I0 is consequently less than the slip of the clutch 3I0.

Because the slip of the clutch 2I0 is less than the slip of the clutch 3I0 and because the torque load becomes less as the car accelerates in rst," they clutch 2| 0 engages as soon as the pressure differential on the clutches becomes `sulclent to permit the clutch 2I0 to transmit the torque required. When the torque load is transmitted through clutch 2I0, torque from the -driving shaft I is transmitted through the fly-wheel 4, key blocks 50, face plate 32|), load dog 340, face plate 330, clutch 2I0, stub shaft 203, second gear 402, second pinion 442, spur pinion 444, spur gear 404, stub shaft 303, and coupler-gear 405 to thev driven shaft 403. Although the clutch'll remains engaged when the clutch 2I0 is engaged and the automobile is driven in second." no.

power istransmitted by the clutch H0, since the second gear 402 in driving the second pinion 442 causes the first pinion 44| to over-driveI the iirst gear 40|, thereby disengaging the over-running clutch 42| of the gear 40|. When the car is driven in second, the ratio 0f slip in the clutch 3I0 is equal, of course, to the ratioof second to direct drive.

The time interval elapsing between the engagement of the clutch ||0 and the clutch 2I0 depends primarily, of course, upon the load conditions. The assumption of the drive from the clutch ||0 by the clutch 2I0 is not only accomplished as soon as the engine is able to carry the load, but the transfer of the load from the clutch l0 to the clutch 2I0 is accomplished very smoothly, since the clutches act smoothly and also since the clutch 2I0 transmits a certain amount of power prior to the complete assumption of the load. Because the over-running clutch 42| of the rst gear -40I disengages .at the instant the clutch 2I0 assumes the load, the transmission does not pass through a neutra] between first and second l The clutch 3 I) assumes the load from the. clutch 2I0 in the same manner that the clutch 2I0 as sumes the load from the clutch I|0,` and, of course, likewise assumes the load smoothly and without passing through a neutral. When the load is carried by the clutch 3I0, torque from the driving shaft I is transmitted directly through the fly-wheel 4, key blocks 50, clutch 3I0, stub shaft 303, and coupier-jgear405 to the driven shaft 403. At the instant the clutch 3I0 assumes the load, the drag of the spur pinion 444 on the gear'ring 434 lof the gear 404 causes the overrunning clutch 424 to disengage.l Thus, no neutral is passed through between second and direct drive, usually termed third or high Because the clutches. 2I0-and |I0' are still e n gaged when the clutch 3I0 is'engaged, there is a tendency for the cone pinion 440 and spur shaft 4|0 to be driven by the second gear 402 during direct drive or "third," which is the normal 0perating drive. However, because no power can be transmitted from the cone pinion 440 when the clutch 424 is disengaged and because a char- 6 acteristic of the over-running clutch 422 is 'that it is substantially disengaged when it can trans-e mit no load, the spur shaft isnot driven appreciably during third," thereby eliminating noise and wear on the one pinion 440, iirst gear 40|,

l0 second gear 402, reverse pinion 445, and reverse idler 455 during normal driving conditions.

When the automobile is driven at maximum speeds or under heavy loads in direct drive, the intake manifold vacuum may fall until the dif ferential pressure on the clutch 3I0 alone would be insuicient to maintainthe clutch in engage ment. However, .because the rseveral clutches in the train are movable axially toward each other, the differential pressures 'and reaction forces on each of the several face plates are additive so that the total effective pressure on any one clutch plate is equal to the differential pressure times lthe total area of the several face plates. Thus, the clutch 3I0, -for example, will be maintained in engagement even when the differential pressure is very low. 'I'he engagement of the clutch 3I0 at high speeds and low differential pressures is insured, however, by the actuation of the centrifugal locking arm 345, 'althoughthe primary purpose of the locking arm346 is to hold the clutch 3I0 in engagement when the throttle is closed whileI the automobile is traveling at high speeds, thereby preventing "free wheeling at speeds in excess of the speed at which the locking `arm 346 engages the lug 344.

If the load demand on the engine should become excessive when the transmission is in thirdlr as for example, when the automobile is driven with the throttle vfully opened up a steep grade, the engine speed will fall, thus disengag-' ing the locking ann 346 and the manifold acuummay fall so low that the differential pressure on the face platesm320 and 330 is insuicient -to hold the clutch 3I0 in engagement. Under such circumstances, the transmission will automatically shift Iback to second or rst, depending upon the magnitude of the load, since the torque load on the clutches 2I0 or |I0 will lbe reduced by driving through the spur gearing and second gear 402 or first gear 40 I To drive the drivenv shaft 403 in reverse, the line to the nipple 66 is opened, usually by releasing the accelerator pedal, thus disengaging thetrain of clutches. 'The operator 4then operates the yoke 401, causing the coupler-gear'405 to be slid into mesh with the reverse idler pinion 45e and uncoupling the shaft 303 from the shaft 465i. When the clutches are then engaged, the transmission drives from the clutch I I0 through the sha-ft |03, gear 40|, cone pinion 440, spur shaft 4I0, rreverse pinion 445,'reverse idler pinion 455, reverse gear 405, and-.shaft 403. While the re verse gear 405 is in'mesh, the torque load may Shifts mechanisms for changing the drive from one ratio to another.' Although in the embodiment disclosed, only three speeds forward are shown, it is obvious that the number of speeds may be varied by increasing or decreasing the number of clutches and corresponding gears in the train, or that suitable over or under drives may be addedyfor example, by adding an additional idler pinion to mesh with the reverse idler pinion 455 and reverse coupler-gear 405.

Further, 'though this invention has been explained as an automobile transmission, it may be used as a transmission for other purposes. Also,

although the differential pressure necessary to engage theclutches is preferably derived from the intake manifold vacuum of an internal cornbustion engine, it may be supplied by other means, as for example, a vacuum pump operated from the driving shaft. This invention, therefore, is not limited, either in whole or in part, to the specific embodiment disclosed but onlyby the appended claims.

What is claimed is:

`1. In a mechanism of the class described, a

driving shaft, a driven shaft, a clutch plate xed to said driven shaft, a face plate spaced from said clutch plate and rotatable with respect to said driven shaft and operatively connected to said driving shaft, said face plate being adapted to engage said clutch plate, means sealing the space between said face plate and said clutch plate, a control system for causing said face plate and said clutch plate to be engaged or disengaged, an auxiliary driven shaft driven through said face plate, speed reduction gearing connecting said auxiliary shaft and said driven shaft, and an over-running clutch interposed between said driven shaft and said auxiliary shaft permitt'ing said driven shaft to be driven through said clutch plate and said face plate when said plates are engaged and through said face plate and said auxiliary shaft when said plates are disengaged.A

2. In a mechanism of the class described, a driving shaft, a driven shaft, a clutchv plate fixed said clutch plate and rotatable with respect to said clutch plate and operatively connected to said driven shaft an inner surface of said face plate being adapted to engage said clutch plate.

means sealing the space lbetween said face plate and said clutch plate, means permitting the creation and maintenance of a fluid pressure differential between the inner and outer surfaces-of said face plate, a control system for regulating the creation and maintenance of said pressure' differentialwhereby lthe said clutch plate and face plate may be engaged or disengaged in direct response to'said pressure differential, an auxiliary shaft operatively connected to'said face plate. speed reduction gearingl connecting said driven shaft and said auxiliary shaft, and an over-running clutch interposed in said gearing adapted to engage when said face plate and said clutch plate are disengaged and to disengage when said plates are engaged.

3. In a mechanism of the class described, a driving shaft, a driven shaft, a clutch plate fixed sealing the space included between the inner surfaces of said face plates, means for creating and maintaining a fluid pressure differential between the inner and outer surfaces of said face plates, a control system forr regulating the creation and maintenance of said ypressure'differential whereby the said clutch plate and face plates may be engaged or disengaged in direct response to said pressure differential, an auxiliary shaft operatively connected to said face plates, speed reduction gearing connecting said driven shaft and` said auxiliary shaft, and an over-running clutch interposed in said gearing adapted to engage when said face platesand said clutch vplate are disengaged and to disengage when said plates are engaged.

driving shaft, a plurality of driven stub shafts,

a plurality of clutch plates, each of said clutch f plates being fixed to a stub shaft, a plurality of pairs of face plates operatively connected to saidV driving shaft and to each other and normally rotatable with respect to said clutch plates, each pair of face plates substantially enclosingr a clutch plate and the spaced inner surfaces of said pairs of face plates being adapted to engage the enclosed clutch plates, means for sealing the space included between the inner surfaces of said pairs of face plates, means permitting the creating and maintaining of a fluid pressure differential between the inner and outer surfaces of said pairs of face plates, a control system for regulating the creation and maintenance of said pressure differential whereby the said pairsV of f-ace plates may engage or disengage the enclosed clutch plates in direct response to said pressure differential, a driven shaft, a coupler normally con'- `necting one of said stub shafts to said driven yto said driven shaft, a faceplate spaced from to said driven shaft, a pair'of falce plates norand operatively connected to eachother and to 'said driving shaft, said face plates substantially enclosing said clutch plate and the spaced inner surfaces of said face plates being adapted -to engage said clutch plate frictionally, means for mainder of said stub shafts to the normally coupled stub shaft, and over-running clutches interposed in said gearing adapted to disengage when the clutch plate connected to said coupled stub shaft is engaged and driven by the pair of face plates enclosing said clutch plate.

5. In a mechanism as described in claim 4, normally disengaged reverse gearing connected to said speed reduction gearing, and means to uncouple said` normally coupled stub shaft and engage said reverse gearing with said driven shaft, whereby the driven shaft may be driven in reverse through the speed reduction gearing by the remainder of said stub shafts not normally coupled to said driven shaft.

6. In' a mechanism of the class described, a driving shaft, a plurality of stub shafts, a train of clutches carried by saidv stub shafts, said train comprising a first clutch, an intermediate clutch, and`a'direct drive clutch, each of said clutches comprising `a clutch plate and a cooperating face plate spaced from the` clutch plate adapted to engage the clutch plate, means sealing the space between the clutch plate and its cooperating face plate, eachof said clutch plates being fxedlto` one of said stub shafts and all of said face plates being operatively connected to each other and to said driving shaft, maximum speed reduction gearing connecting the stub shaft carrying the first clutch to the stub shaft carrying the direct drive clutch, a first over-running clutch interposed in said maximum speed reduction gearing,` intermediate speed reduction gearing onnecting a stub shaft carrying an interme iate clutch to. the stub shaft carrying said direct drive clutch, an intermediate over-running clutch :escasos interposed in said intermediate speed reduction gearing, and means causing said clutches in said train to engage and drive said direct drive stub shaft progressively, said rst over-running clutch being engaged when said first clutch drives and being disengaged when' an intermediate clutch drives, and said intermediate over-running clutch being disengaged when said .direct drive clutch is engaged. '"m

7. In a mechanism of -the class described, a plurality of'shafts comprising a first shaft, an intermediate shaft, and a direct drive shaft, maximum speed reduction gearing connecting 'said first shaft and said direct drive shaft, a first over-running clutch interposed in said maximum speed reduction gearing, intermediate speed reduction gearing connecting an intermediate shaft and said direct drive shaft, an intermediate over-running clutch interposed in said intermediate speed reduction gearing, and means for drivi-ng progressively said first shaftJ an intermediate shaft, and vsaid direct drive shaft, said first over-running clutch being engaged when only said first shaft drives and being disengaged when an intermediate shaft drives,y and said intermediate over-running clutch being engaged when said intermediate shaft drives and being disengaged when saiddirect drive shaft drives.

8. In a mechanism of the class described, a driving shaft, a plurality of shafts. comprising a direct drive shaft and a plurality of tubular auxiliary shafts concentric, rotatable, and axially displaceable with respect to said direct drive shaft, and each other, a train of clutches carried by said shafts, said train comprising a first clutch carriedv by a first auxiliary shaft, an intermediate clutch carried by an intermediate auxiliary shaft, and a direct drive clutch carried by said'direct drive shaft, each clutch comprising a clutch plate fixed to the carrying shaft, and a pair offace plates substantially enclosing said clutch plate and normally spaced therefrom to provide a. good running fit, means for sealing the space included between the pair of face plates, and means operatively .connecting said face plates of said pairs to eachother and resiliently restraining said face plates from rotation and, axial displacement with respect to -each other, all of said face plates 'in said train of clutches being operatively connected to each other and tosaid driving shaft, means for creating a fluid pressure differential between the inner and outeresurfaces of said face plates in said clutches whereby saidpairs of face plates in said 'clutches engage the enclosed clutch plates and the axial displacement'of theseveral shafts with' respect to each other permits the additive application of the differential pressuresL onrthe several clutches, and means for causing the progressive engagement of said first clutch,

an intermediate clutch, and the direct drive clutch upon the application of a startingfload.

9. In afmechanism as f described in claim 8,

stiiienlng and heat-dissipating fins located onv the outer surfaces of said face plates and means "-fpermitting. the access of a cooling medium to -the heat-dissipatingfins on an intermediate clutch through 'an adjacent clutch in .said train of clutchesj' 10;-In a mechanism of the class described, a

driving shaft.' a direct drive shaft, an auxiliary shaft concentric with said dlrect driveshaft, a direct drive clutch vcarried by said direct drive shaft, an auxiliary clutch carried by said auxiliary shaft, each of said clutches comprising a clutch 'plate fixed to the carrying shaft and a pair of face plates substantially enclosing said vclutch plate and normally spaced therefrom by at least a good running fit, means for sealing the space included between said pair of face plates, and resilient means for restraining the rotation and axial movement of said face plates with respect to each other, means for operatively connecting all of the face plates of said clutches to each other and to said driving shaft, means for creating a fluid pressure differential between the inner and outer surfaces of said clutches whereby the pairs of normally spaced face plates engage the substantially enclosed clutch plates and cause the driving shaft to drive the auxiliary shaft and the direct drive` shaft. 11. In a mechanism as described in claim 10,

. means ,connecting the sealed space included between the pair of face plates of the direct drive clutch with the sealed space included between the pair of face plates of an auxiliary clutch.

12. In a mechanism of the class described,A a

driving shaft, a. driven shaft, a clutch plate fixed tothe driven shaft, a face plate spaced from said clutch plate and operatively connected to the driving shaft, the inner surface of said face plate being adaptedto frictionally engage said clutch plate and to be spaced from said clutch plateat'o disengage said clutch plate, means for sealing the space between said clutch plate and said face plate, and means for creating a fluid pressure differential between the inner surface of said face plate and the outer surface of said face plate, whereby the said face plate will engage the said clutch'plate in response tol the fluid pressure differential and cause said driving' shaft to drive said driven shaft.

13. In a mechanism of the class described, ar

driving shaft, a driven shaft, a clutch platexed Eto said driven shaft, a' pair of face plates operwhich the means permitting the creation of fluid J pressure y,differential comprise a fluid pressure conduit, a xed collector ring connected to said conduit, a-port ring carried by a face plate and received in said collector ring and having a port lopeninginto the sealed space included between the pair of face plates whereby fluid pressure in said vsealed space may vary according tothe fluid l pressure in said conduit.

15. A mechanism as described in claim 13, including means operatively connecting said face plates' to each other comprising a resilient load dog connected to each of said face plates and restraining said face plates fromvrotation andy axial displacement with respect to each other. 16. A mechanism 'as described in claim 13, in-

cluding means operatively. connecting said face plates to each other comprising?"4 a resilient load dog connected to each of said face plates and restraining said face plates vfrom rotation and axial displacement with respect to each other, and Wedge lugs secured to said face plates, said wedge lugs being vnormally spaced from each other but adapted to engage when one of said face plates tends to lead the other of said face plates in the direction of rotation when said face plates are under load,v thereby limiting the lead of the one face plate and wedging the pair of face plates into engagement with the said enclosed clutch plate.

17. A mechanism as describedin claim 13, including means operatively connecting said face v plates to each other comprising a'resilient load dog connected to each ofsaid face plates and restraining 'said face plates from rotation and axial displacement with respect to each other, and centrifugal locking means comprising a lug secured to one face plate and a centrifugal locking arm pivotally mounted on the second face plate, said locking arm comprising an arm, a wedge fac'e on one end of said arm` and normally disengaged vfrom said lug, anda weight secured to the other end vof said arm, and a spring connecting said arm on said second face plate and adapted to maintain said locking arm out of engagement with saidlug below a predetermined rotational speed.

18. A mechanism as claimed in claim 8 including wedge lugs secured to the face plates of said first clutch and ycentrifugal locking means secured to the face plates of said direct drive clutch.

19. A mechanism as described in claim 13, including means operatively connecting said pair of face plates to said driving'shaft comprising a ily. wheel secured to said driving shaft and a resilient key engaging said fly-wheel and one of said' face v plates.

20. A mechanism as described in claim 4 and accelerator valve to said means permitting the creating and maintaining of a fluid pressure difventport when said accelerator pedal is not actuated.

22. In a mechanism of the class described adapted for use in anautomobile driven by an Y internal combustion engine, a normally disengaged clutch directly responsive to a fluid pressure differential, an intake manifold, an 'accelerator pedal, an accelerator valve responsive to said accelerator pedal, a clutch line from said accelerator valve to said clutch, a manifold line from said manifold to said valve, and 'a vent port in said valve normally open to atmospheric pressure, said valve having passages connecting said manifold line to said clutch line when said accelerator is actuated to engage 4said clutch and opening said clutch line to said vent port when said pedal is not actuated to disengage said clutch, a vacuum storage tank, an auxiliary manifold line from said manifold to said tank, a tank line from said tankAto said valve, and normally open check valves lin each of said manifold line and said auxiliary manifold line, said accelerator valve connecting said tank line to said manifold line and said clutch line when said accelerator .pedal is substantially fully actuated and said check valves closing said manifold and auxiliary manifold lines when the vacuum 'in said'tank is greater than the vacuum in said manifold.

23."In a mechanism of the class described adapted for use in an automobile driven by an internal combustionl engine, a normally disengaged clutch directly responsive to a fluid pressaid manifold to said valve, and a vent port in said vvalve normally open to atmosphericv pressure, said valve having.y passages connecting said manifold line to said clutch line when said accelerator is actuated to engage said clutch and opening said clutch line to saiod vent port when said pedal is not actuated to disengage .said

- clutch, a brake pedal, a brake valve responsive to the actuation of said brake pedal, a branch manifold line connecting said manifold line to said brake valve, a branch clutch line connecting said brake valve to said clutch line, a first vent and a second vent in said brake valve open to atferential between the inner and outer surfaces e of said pairs of face plates, and a vent port in said accelerator valve, said accelerator valve connecting said manifold line to said clutch line when said accelerator pedal is actuated and opening said clutch line to said vent port when said accelerator pedal is not actuated.

21. In a mechanism as described in claim 13 in which the means permitting the creation of fluid pressure r'differential comprise a clutch dine, a xed collector ring connected to said clutch line, a port ring carried by ,a face plate and received in said collector ring and having a. port opening into the sealed s'pace included between the pair of face plates whereby fluid pressure in said sealed space may varyaccording to the fluid pressure in Asaid clutch line, an automobile accelerator pedal, an' accelerator valve responsive to said ac-4 celerator pedal, a source of vacuum, a manifold line from said source to said accelerator valve, and a vent port in said accelerator valve, said Y acceleratorvalve connecting said manifold line mospher'ic pressure and vent lines connecting said brake valve to said accelerator valve vent port, said brake valve, when said accelerator valve is not actuated, connecting said rst vent to said accelerator valve vent port when said 'brake pedall is not actuated; closing said first vent and connecting said branch manifold line and said branch'clutch line when said brake y f pedal is partially" actuated; connecting said second vent to said accelerator valve vent port when said brake pedal is substantially fully actuated.

24. In a mechanism of the class described, a

driving shaft, a driven shaft, a clutch plate xed to said driven shaft, a face plate spaced from said v clutch plate and operatively connected to said driving shaft, means sealing the space between said face plate and said clutch plate, fluid pressure means adapted to cause said face plate and clutch plate to engage in direct response to said fluid pressure, and means for equalizing the pressure of fluid entrained between said face plate/ r` for causing said face plate and said clutch plate to engage whereby the driving shaft drives said driven shaft through said engaged clutch plate and face plate, and means substantially preventing the stress on said clutch plate from distorting said clutch plate.

26. In a...mechanism of the class described adapted for use vin an automobile driven by an internal combustion engine, a clutch directly responsive to a fluid pressure diil'erential, an intake manifold, an accelerator pedalv means responsive `to the actuation of said accelerator pedal connecting" said manifold to said clutch and thereby engaging said clutch when said accelerator pedal is actuated and disconnecting salad manifold and clutch and thereby disengaging said clutch when said accelerator pedal is not actuated, a brake pedal, and means vresponsive to the actuation of said brake pedal and, when said accelerator pedal is not actuated, connecting said manifold tov said clutch and thereby engaging said clutch when said brake pedal is partially actuated and disconnecting said manifold and said clutch and thereby disengaging said clutch when said brake pedal is substantially fully operated.

27. A clutch mechanism comprising a rst driving plate and a second driven plate mounted rotatably and coaxially with respect to said ilrst driving plate, said ilrst and second plates being axially movable relative to each other and normally spaced from each other, fluid pressure sealing means operativelyengaged between said rst plate and said second plate to seal the space between said first and second plates, means to create a uid pressure differential between the pressure on the outer surface of one plate and the fluid pressure in the space enclosed between said rst and second plates by said sealing means t move said plates into frictional engagement with each other wherebyvsaid first driving plate will drive said second driven plate, and means to equalize the fluid pressure in the space between said rst and second plates and the iluid pressure on the outer surface of said one plate torelease said rst plate from a driving engagement with said second plate.

DAVID J. DOLAN. 

